Taping the seams of oil boiler exhaust pipe vent pipe?
This heating season, I've continued to find black soot below the exhaust vent pipe of our 1995 Vaillant oil boiler. It was cleaned less than 5 months ago. Given the location of the soot, I'm assuming it's escaping the seams of the vent pipe, which has also been cleaned.
Our boiler technician recommended taping the seams of the exhaust pipe, as seen in the photo. Is there any concern with taping the seams of this pipe with foil tape? Do the seams contribute to draft? I've never seen one taped in other homes, but it seems it would help solve the problem, unless it would cause another problem (such as draft).
Third photo is taken before the tape was placed.
Comments
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The burner shouldn't be making soot in any significant quantity to be a problem like that.
Did the tech who cleaned it use a combustion analyzer to tune the burner when it was serviced?
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Agree with @KC_Jones . get the boiler properly cleaned. There is an often neglected place that needs to be opened and cleaned with a brush and soot vacuum cleaner. Once the boiler is thoroughly cleaned, the proper adjustments should be made so the burner does not make any soot. That is done with a combustion analyzer and a smoke stop tester.
As far as foil tape on the seams of oil boiler vent connectors (Smoke Pipe), that is not a recommended use of foil tape
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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thank you. The boiler was last cleaned in July, and we had it cleaned again today. The tech only performed a smoke test (which was reportedly satisfactory); they said they reserve combustion analyzer tests for new installations only to satisfy FD permitting.
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They are wrong. They should be doing a full analysis. In addition to filter change, nozzle change, cleaning etc. they have to do the analysis to ensure all the changes they made are working correctly.
What's really sad is they have soot, an obvious sign the analysis has to be done, and their "solution" is to ignore that entirely and basically tell you everything is fine.
"Everything is fine, call us next year when it's filthy to clean it out again." What they don't tell you is it's their fault it's dirty in the first place.
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That was my assumption. This is the second company to service the boiler without combustion testing. It's been difficult, as oil companies around here in MA will only deliver oil if they are the service provider, so finding other service means having to switch oil delivery, which is frustrating.
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Shouldn't really need to seal the vent pipe if the joints are properly assembed.. If you do I would use high temp RTV which you can buy in a big box where they sell wood and coal burning inserts.
I agree with the need for proper service with combustion testing.
In my opinion the smoke pipe should be removed and cleaned and checked along with a look up the chimney. Maybe not required every year but every 2-3-4 years depending on the combustion.
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In barely upstate NY I found my oil supplier wasn't doing combustion tests so I found a local company that did it right (even replacing my nozzle, imagine!). The second company is not an oil supplier, so I still have my old supplier—I don't know if it's legal for them to mandate they are the service provider in order to supply oil, but even if they do, I will pay these other folks on top of them.
Sometimes I think I am unfairly harsh to oil suppliers, then I read threads like this and think "nope"
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el1 -
THIS v v v v v
I had a customer with a boiler just like this in the 1990s. I cleaned the boiler three years in a row without knowing about this hidden access panel. After the third year I could not get the over fire pressure below the recommended +.02 maximum. I checked with other technicians about this and was informed about the "secret panel".
After discovering how to access that panel, I found that the second pass section of the boiler was almost completely blocked with debris. Once that was thoroughly cleaned, I was able to get the burner to operate with a zero smoke spot. The over-fire pressure was between +.005 and +.01 as recommended by the manufacturer.
You may want to open this secret panel and look inside the boiler passage to see if it is clean. ALSO tell the technician to bring the combustion analyzer with them when they return to clean the secret panel. Otherwise you will not pay for the service and you will purchase your oil and service from another provider.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Incredibly insightful, thank you!
For my own curiosity, if combustion is less than desirable such as high CO, is that ultimately a risk to us? Even with poor combustion, shouldn't those gasses be contained within the boiler and flue pipe with negative pressure from the chimney draft?
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@jgvasa said:"Even with poor combustion, shouldn't those gasses be contained within the boiler and flue pipe with negative pressure from the chimney draft?"
I would think so. Unless of course there is a blockage in the chimney, vent connector or boiler itself. If that happens, then maybe all the air tight seams and gaskets that keep the soot and CO from exiting the boiler flue passages connector and chimney might fail. If that happens when you are sleeping and the boiler continues to heat your home, those failed seams may let that CO and soot exit the system inside your home. If that happens and you wake up dead the next morning, I think you would have wanted the technician to have completed the proper adjustments to avoid such a problem.
But that is just one old man's opinion.
Disclamer:
"Wake up dead" is a figure of speech to indicate that you may be less than healthy as a result of smelling flue gasses from your heating appliance. It does not in any way advocate for or against any health related issues that may or may not result from improper venting of flue gas escape. Other forms of health related problems may also have their source from other appliances and mechanical devices that you interact with on a daily basis. Automobile crashes are the number one cause of traffic related injuries. It has been said that more people die from traffic accidents than plane crashes. So with that logic you may want to purchase airfare until you can have that heater properly serviced with combustion instruments.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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out the company
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Agree with combustion analysis, full comprehensive sweeping, chimney with proper liner swept and intact. Foil tape specifically not allowed per NFPA 211. Each joint should have a minimum of 3 equidistantly spaced screws. No seams btw 5-7 O'clock. Add support at both offsets.
There is not heavy soot tracking in the gate of the barometric damper, so I doubt you're getting it into the room from the joints. If you are , fix the negative pressure in the CAZ and re-check the venting, firing, etc.
Smoke test number is almost useless. It is a crude measure of how bad your bad is. Cannot tell you how good your good is. For that, you need the analyzer.
I did not see a test hole in the chimney connector between the barometric damper and the chimney to measure chimney draft, which is necessary to set the counterweight. The counterweight needs to be moved over to the left hand or 'H'' position for a horizontal (greater than 45 degrees from vertical) and the weight adjusted using a draft gauge in the hole specified above. ,
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I've worked on those boilers with both the Beckett AFG (which you have), and the Carlin 100. The Valiant is a PITA to clean (top and front access), and the burner absolutely needs adjustment. And an analyzer tells you what needs adjustment.
I would recommend an oil delay valve for pre and post purge. The existing primary can be programmed to accept it.
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